|
On the topic of torque vs horsepower:
As TrackRat has already so eloquently put, one is a function of the other. Ultimately, horsepower is the number you should be concerned with if you're after performance, and more specifically, the curvature of horsepower production. Peak horsepower is an interesting number, but if you look at a lot of dyno charts, you'll find that a strong performing car has a dyno chart that rises early, stays strong, then drops after its peak. As far as performance goes, torque numbers aren't terribly important.
Why is that? Because for any specified horsepower output, you can generate equal torque through gearing. That is to say, two engines that generate 300 HP at a given RPM can generate equal torque at any given RPM. An example using the following formulas:
hp = tq(rpm)/5252
tq = hp(5252)/rpm
Engine 1
300 HP @ 5000 RPM
Engine 2
300 HP @ 8000 RPM
Q: Which of these engines, when operating at peak HP, is capable of producing more torque at 2500 RPM (through a gearbox)?
A: Neither, they would both produce roughly 630 lb ft through a gearbox (unaccounted for loss). Engine 1 would require a gearing factor of 2:1 and engine 2 would require a gearing factor of 3.2:1. Since both engines must operate through a gearbox, both will suffer losses and we can assume any discrepancy between gearboxes will be negligible.
This is why tq vs hp doesn't matter. With the appropriate gearing, you can apply the same force at the ground. Torque is a measure of force only. I can generate 400 lb ft of torque with a torque wrench. If you put me under the hood of your car with that torque wrench attached to the input shaft of the transmission, how fast do you think you'll go?
If you want to go fast, you need lots of horsepower. End of story.
|